Method of electric welding.



G. E. THOMPSON. METHOD OF ELECTRIC WELDING.

APPLIOATIOK IILBD mm: 11, 1907.

910,434. mm m 19, 1909.

7/2! eases. f tvewfcr' 601. am. 4 QM awffifl UNITED STATES PATENTOFFICE...

CHARLES E. THOMPSON,

OF. CLEVELAND, OHIO, ASSIGNOR, BY

MESNE AssieNMEN'rs, To

- THE ELECTRIC WELDING PRODUCTS COMPANY, OF CLEVELAND, OHIO, ACORPORATION OF OHIO.

METHOD OF ELECTRIC W'EIZDING'.v

Specification of Letters Patent. Application filed June 11, 1907. SerialNo. 378,487.

Patented i'an. 19, 1909.

To all whom it may concern:

Be it known thatfI, CHARLES E. THOMP- son, a citizen of the UnitedStates, resident of Cleveland, county of Cuyahoga, State of Ohio, haveinvented a new and useful Improvement in Methods of Electric Welding,

, of which the following is a specification, the

resents in side elevation a brass part and an principle of the inventionbeing herein explained and the best mode in which I have contemplatedapplying that principle, so as to distinguish it from other inventions.

My invention relates to the art of electric welding and has )articularregard to the welding together by means of the electric current of partshaving diverse degrees of electrical conductivity.

Said invention, in other words, has its object the provision of animproved method whereby parts, composed of metals thus differin may bereadily and effectively joined toget er.

To the accomplishment of such and related objects, said inventionconsists of the steps hereinafter fully described and specifical y setforth in the claims.

The annexed drawing and the following descri tion set forth in detailcertain steps embo ying the principle of my invention, the disclosedmethod, however, being but one of various methods in which the principleof my invention may be employed.

In said annexed drawing Figure 1 repironor steel part designed toconstitute in their assembled form the head and body, respectively, of abolt or like object, such parts being shown in a form adapting them foruse in connection with my improved method of welding; Fig. 2 is acentral longitudinal cross-section of such object upon the completion ofthe operation of welding; and Fig. 3 is a side elevation of suchcompleted ob ect.

As indicated, for a specific exemplification of the working out of mymethod I have adopted the making of brass headed bolts or brass capscrews such as have recently found a large field of usefulness,particularly in connection with the manufacture of automobiles and othermachinery, where it is desired to employ a fastener of the character ofa cap screw that will have a head easily polished without the same timehaving the fastener of inferior tensile strength as would be the casewere the whole screw made of brass.

Now in the welding together of a brass part and a steel part, owing tothe higher egree of conductivity possessed by the brass, suchconductivity I bein approximately five times that of steel, t etemperature of the former will rise much less rapidly than that of thelatterupon the passage through the parts .of the heating electriccurrent. Accordingly before the steel reaches its melting point ofapproximately 2,500 degrees F. the portion of the brass part in contactwith the steel art will have become dissipated or burned out since thisresult takes place at a proximately 1,800 degrees F. The metho whereby Iproposeto overcome these several difliculties consists, generallystated, in reducin the cross sectional area of the face oft e parthaving the higher degree of conductivity below the area of the face ofthe other part, so that the two areas in uestion are in effectproportioned inverse y to the res ective conductivities of the saidparts. 0 this end, in the example chosen for illustration, Fig. 1, thebrass head A which is designed to be joined to the steel body B, isprovided with a welding lug ,a of conical or rather frusto-conical form,the area of its apex bearing the ratio above indicated towards the areaof the end of the bolt body B. The welding operation, proper, thenconsists in contact and keepin them un er a steady pressure while at thesame time a heating electric current is passed throu h the parts. Thedevice whereby this operatlon is accomplished may be various, any of theseveral well known forms of electric welding apparatus being obviouslyadaptable to the use in hand. Illustration of such apparatus isaccordingly omitted. The flow of current being limited to. that whichcan be accomplished by the reduced contact area of the welding lug, therise in tem erature of the brass head can be controlled and thecontiguous end of the bolt body rendered plastic before such headbecomes so fluid as to run. The two' parts being kept under a steadypressure,'the brass closes m as it fuses, consequently increasing thearea of contact and correspondingly extending the heated area on thesteel end. By the time that the con- -my invention may be employedinstead of ical portion of the brass has been fused the contact face ofthe steel is brought to the required temperature to perform the weldingoperation. The result is hence a firm union 5 of the character clearlybrought forth in Fig. 2 of the drawings, representing actual operativeconditions, wherein it is seen that the brass welding lug has remainedsufiicicntly cohesive and integral to impress its form upon the meetingend of the steel rod. Furthermore such head is not simply superficiallystuck onto the bolt end but as also shown in the figure last ofreference, and in Fig. 3, filaments or fringes of the respectivematerials inter-twine or interlock and thus make the unison a dove-tailjoint 18 it were, indicating that such materials are of sub stantiallyequal plasticity in spite of their unlike conductivities.

Other modes of applying the principle of the one explained, change beingmade as regards the process herein disclosed, provided the step or stepsstated by any one of the following claims or the equivalents of suchstated step or steps be employed.

I therefore particularly point out and distinctly claim as my invention11' The method of electrically welding together parts of diverse degreesof conductivity, which consists in first reducing the cross-sectionalarea of the face of the part having the higher degree of conductivitybelow the area of the face of the other part, 35

,maintaining such faces in contact under a steady pressure, and thenpassing a heating electric current through the same.

2.- =The method of electrically welding together parts of diversedegrees of conducti'vity, whichconsists in first proportioning theci'oss' 'sec'tion areas of the faces of the arts inversely to therespective conductivlties' of said parts, maintaining such faces incontact under a steady pressure, and then passing a -heating electriccurrent through the same.

3. The method of electrically welding a brass to a steel part, whichconsists in first reducing the cross-sectional area of the face of thebrass part below the area of the face of the steel part, maintainingsuch faces in contact under a steady ressure, and then passing a heatingelectnc current through the same. 1

4. The method of electrically welding together a brass to a steel part,which consists in first reducing the cross-sectional area of the face ofthe brass part to approximately one-fifth that of the steel part,bringing such faces into contact, and then assing a heating electriccurrent throu h t e same.

5. The method of electrically welding onto a body of one degree ofconductivity a head having a greater conductivity, which consists infirst providing the latter with a welding lug of frusto-conical form,the area of the apex of said lug bein proportioned to that of the end ofsaid body inversely to the respective conductivities of said head andbody, bringing said lug and body into contact, and then passing aheating electric current through the same.

6. The method of electrically welding a' brass head onto a bolt-body ofsteel, which consists in first, providing said head with a welding lugof frusto-conical form, maintaining said lug and body in contact under asteady pressure, and then passing a heating electric current through thesame.

7. The method of electrically welding a brass head onto a bolt-body ofsteel, which consists in first providing said head with a welding lug offrusto-conical form, the area of the apex of such lug beingapproximately one-fifth that of the end of the bolt body, bringing saidlug and body into contact, and then passing a heating electric currentthrough the same.

Signed by me this 24th day of May, 1907.

CHARLES E. THOMPSON.

Attested by E. B. Row, JNo. F OBERLIN.

